Bump Checkstyle to 8.20 (#7651)

* Bump Checkstyle to 8.20

Moderate severity vulnerability that affects:
com.puppycrawl.tools:checkstyle

Checkstyle prior to 8.18 loads external DTDs by default,
which can potentially lead to denial of service attacks
or the leaking of confidential information.

Affected versions: < 8.18

* Oops, missed one

* Oops, missed a few

cloud/aws-common/src/main/java/org/apache/druid/common/aws/ConfigDrivenAwsCredentialsConfigProvider.java

@@ -58,5 +58,7 @@ public class ConfigDrivenAwsCredentialsConfigProvider implements AWSCredentialsP
   }
 
   @Override
-  public void refresh() {}
+  public void refresh()
+  {
+  }
 }

core/src/main/java/org/apache/druid/common/utils/ByteUtils.java

@@ -31,5 +31,7 @@ public final class ByteUtils
     return result;
   }
 
-  private ByteUtils() {}
+  private ByteUtils()
+  {
+  }
 }

core/src/main/java/org/apache/druid/common/utils/IntArrayUtils.java

@@ -60,5 +60,7 @@ public class IntArrayUtils
     } while (nextIndex != startIndex);
   }
 
-  private IntArrayUtils() {}
+  private IntArrayUtils()
+  {
+  }
 }

core/src/main/java/org/apache/druid/concurrent/Threads.java

@@ -55,5 +55,7 @@ public final class Threads
     }
   }
 
-  private Threads() {}
+  private Threads()
+  {
+  }
 }

core/src/main/java/org/apache/druid/data/input/Rows.java

@@ -127,5 +127,7 @@ public final class Rows
     return metricValueString;
   }
 
-  private Rows() {}
+  private Rows()
+  {
+  }
 }

core/src/main/java/org/apache/druid/java/util/common/CloseableIterators.java

@@ -92,5 +92,7 @@ public class CloseableIterators
     return wrap(innerIterator, null);
   }
 
-  private CloseableIterators() {}
+  private CloseableIterators()
+  {
+  }
 }

core/src/main/java/org/apache/druid/java/util/common/granularity/AllGranularity.java

@@ -34,7 +34,9 @@ public class AllGranularity extends Granularity
    * This constructor is public b/c it is serialized and deserialized
    * based on type in GranularityModule
    */
-  public AllGranularity() {}
+  public AllGranularity()
+  {
+  }
 
   @Override
   public DateTimeFormatter getFormatter(Formatter type)

core/src/main/java/org/apache/druid/java/util/common/granularity/NoneGranularity.java

@@ -31,7 +31,9 @@ public class NoneGranularity extends Granularity
    * This constructor is public b/c it is serialized and deserialized
    * based on type in GranularityModule
    */
-  public NoneGranularity() {}
+  public NoneGranularity()
+  {
+  }
 
   @Override
   public DateTimeFormatter getFormatter(Formatter type)

core/src/main/java/org/apache/druid/java/util/common/io/NativeIO.java

@@ -85,7 +85,9 @@ public class NativeIO
 
   private static native int sync_file_range(int fd, long offset, long len, int flags);
 
-  private NativeIO() {}
+  private NativeIO()
+  {
+  }
 
   private static Field getFieldByReflection(Class cls, String fieldName)
   {

core/src/main/java/org/apache/druid/java/util/emitter/core/HttpEmitterConfig.java

@@ -34,7 +34,9 @@ public class HttpEmitterConfig extends BaseHttpEmittingConfig
   /**
    * For JSON deserialization only. In other cases use {@link Builder}
    */
-  public HttpEmitterConfig() {}
+  public HttpEmitterConfig()
+  {
+  }
 
   public HttpEmitterConfig(BaseHttpEmittingConfig base, String recipientBaseUrl)
   {

core/src/main/java/org/apache/druid/java/util/emitter/factory/LoggingEmitterFactory.java

@@ -28,7 +28,9 @@ import org.asynchttpclient.AsyncHttpClient;
 
 public class LoggingEmitterFactory extends LoggingEmitterConfig implements EmitterFactory
 {
-  public LoggingEmitterFactory() {}
+  public LoggingEmitterFactory()
+  {
+  }
 
   @Override
   public Emitter makeEmitter(ObjectMapper objectMapper, AsyncHttpClient httpClient, Lifecycle lifecycle)

core/src/main/java/org/apache/druid/java/util/http/client/HttpClientConfig.java

@@ -218,7 +218,9 @@ public class HttpClientConfig
     private CompressionCodec compressionCodec = DEFAULT_COMPRESSION_CODEC;
     private Duration unusedConnectionTimeoutDuration = DEFAULT_UNUSED_CONNECTION_TIMEOUT_DURATION;
 
-    private Builder() {}
+    private Builder()
+    {
+    }
 
     public Builder withNumConnections(int numConnections)
     {

core/src/main/java/org/apache/druid/utils/CloseableUtils.java

@@ -45,5 +45,7 @@ public final class CloseableUtils
     }
   }
 
-  private CloseableUtils() {}
+  private CloseableUtils()
+  {
+  }
 }

core/src/main/java/org/apache/druid/utils/CollectionUtils.java

@@ -68,5 +68,7 @@ public final class CollectionUtils
     };
   }
 
-  private CollectionUtils() {}
+  private CollectionUtils()
+  {
+  }
 }

core/src/test/java/org/apache/druid/java/util/common/BufferUtils.java

@@ -36,5 +36,7 @@ public final class BufferUtils
     return totalMemoryUsed;
   }
 
-  private BufferUtils() {}
+  private BufferUtils()
+  {
+  }
 }

core/src/test/java/org/apache/druid/java/util/emitter/core/CustomEmitterFactoryTest.java

@@ -69,16 +69,24 @@ public class CustomEmitterFactoryTest
     }
 
     @Override
-    public void start() {}
+    public void start()
+    {
+    }
 
     @Override
-    public void emit(Event event) {}
+    public void emit(Event event)
+    {
+    }
 
     @Override
-    public void flush() {}
+    public void flush()
+    {
+    }
 
     @Override
-    public void close() {}
+    public void close()
+    {
+    }
   }
 
   @Test

extendedset/src/main/java/org/apache/druid/extendedset/intset/EmptyIntIterator.java

@@ -30,7 +30,9 @@ public final class EmptyIntIterator implements IntSet.IntIterator
     return INSTANCE;
   }
 
-  private EmptyIntIterator() {}
+  private EmptyIntIterator()
+  {
+  }
 
   @Override
   public boolean hasNext()

extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/ConciseBitMapFactory.java

@@ -27,7 +27,9 @@ public class ConciseBitMapFactory implements BitMapFactory
 {
   private static final BitmapFactory bitmapFactory = new ConciseBitmapFactory();
 
-  public ConciseBitMapFactory() {}
+  public ConciseBitMapFactory()
+  {
+  }
 
   @Override
   public MutableBitmap makeEmptyMutableBitmap()

extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/JavaBitMapFactory.java

@@ -27,7 +27,9 @@ public class JavaBitMapFactory implements BitMapFactory
 {
   private static final BitmapFactory bitmapFactory = new BitSetBitmapFactory();
 
-  public JavaBitMapFactory() {}
+  public JavaBitMapFactory()
+  {
+  }
 
   @Override
   public MutableBitmap makeEmptyMutableBitmap()

extensions-contrib/distinctcount/src/main/java/org/apache/druid/query/aggregation/distinctcount/RoaringBitMapFactory.java

@@ -27,7 +27,9 @@ public class RoaringBitMapFactory implements BitMapFactory
 {
   private static final BitmapFactory bitmapFactory = new RoaringBitmapFactory();
 
-  public RoaringBitMapFactory() {}
+  public RoaringBitMapFactory()
+  {
+  }
 
   @Override
   public MutableBitmap makeEmptyMutableBitmap()

extensions-contrib/moving-average-query/src/test/java/org/apache/druid/query/movingaverage/MovingAverageQueryTest.java

@@ -384,7 +384,9 @@ public class MovingAverageQueryTest
         new ServiceEmitter("", "", null)
         {
           @Override
-          public void emit(Event event) {}
+          public void emit(Event event)
+          {
+          }
         },
         baseClient, warehouse, retryConfig, jsonMapper, serverConfig, null, new CacheConfig()
     );

extensions-contrib/statsd-emitter/src/main/java/org/apache/druid/emitter/statsd/StatsDEmitter.java

@@ -83,7 +83,9 @@ public class StatsDEmitter implements Emitter
   }
 
   @Override
-  public void start() {}
+  public void start()
+  {
+  }
 
   @Override
   public void emit(Event event)
@@ -169,7 +171,9 @@ public class StatsDEmitter implements Emitter
   }
 
   @Override
-  public void flush() {}
+  public void flush()
+  {
+  }
 
   @Override
   public void close()

extensions-contrib/thrift-extensions/src/main/java/org/apache/druid/data/input/thrift/ThriftExtensionsModule.java

@@ -44,5 +44,6 @@ public class ThriftExtensionsModule implements DruidModule
 
   @Override
   public void configure(Binder binder)
-  { }
+  {
+  }
 }

extensions-core/avro-extensions/src/main/java/org/apache/druid/data/input/avro/AvroExtensionsModule.java

@@ -42,7 +42,9 @@ import java.util.List;
 
 public class AvroExtensionsModule implements DruidModule
 {
-  public AvroExtensionsModule() {}
+  public AvroExtensionsModule()
+  {
+  }
 
   @Override
   public List<? extends Module> getJacksonModules()
@@ -62,7 +64,8 @@ public class AvroExtensionsModule implements DruidModule
 
   @Override
   public void configure(Binder binder)
-  { }
+  {
+  }
 }
 
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = GsonJsonUtil.class)

extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/RawInputValueExtractor.java

@@ -31,7 +31,9 @@ public class RawInputValueExtractor implements ComplexMetricExtractor
     return EXTRACTOR;
   }
 
-  private RawInputValueExtractor() {}
+  private RawInputValueExtractor()
+  {
+  }
 
   @Override
   public Class<?> extractedClass()

extensions-core/hdfs-storage/src/main/java/org/apache/hadoop/fs/HadoopFsWrapper.java

@@ -35,7 +35,9 @@ public class HadoopFsWrapper
 {
   private static final Logger log = new Logger(HadoopFsWrapper.class);
 
-  private HadoopFsWrapper() {}
+  private HadoopFsWrapper()
+  {
+  }
 
   /**
    * Same as FileSystem.rename(from, to, Options.Rename). It is different from FileSystem.rename(from, to) which moves

extensions-core/protobuf-extensions/src/main/java/org/apache/druid/data/input/protobuf/ProtobufExtensionsModule.java

@@ -44,5 +44,6 @@ public class ProtobufExtensionsModule implements DruidModule
 
   @Override
   public void configure(Binder binder)
-  { }
+  {
+  }
 }

extensions-core/protobuf-extensions/src/test/java/org/apache/druid/data/input/protobuf/ProtoTestEventWrapper.java

@@ -25,7 +25,9 @@ package org.apache.druid.data.input.protobuf;
 @SuppressWarnings("ALL")
 public final class ProtoTestEventWrapper
 {
-  private ProtoTestEventWrapper() {}
+  private ProtoTestEventWrapper()
+  {
+  }
 
   public static void registerAllExtensions(
       com.google.protobuf.ExtensionRegistryLite registry

indexing-service/src/main/java/org/apache/druid/indexing/common/Counters.java

@@ -47,5 +47,7 @@ public final class Counters
     return counter.incrementAndGet();
   }
 
-  private Counters() {}
+  private Counters()
+  {
+  }
 }

indexing-service/src/main/java/org/apache/druid/indexing/common/TaskRealtimeMetricsMonitorBuilder.java

@@ -30,7 +30,9 @@ import org.apache.druid.segment.realtime.RealtimeMetricsMonitor;
 
 public class TaskRealtimeMetricsMonitorBuilder
 {
-  private TaskRealtimeMetricsMonitorBuilder() {}
+  private TaskRealtimeMetricsMonitorBuilder()
+  {
+  }
 
   public static RealtimeMetricsMonitor build(Task task, FireDepartment fireDepartment)
   {

indexing-service/src/test/java/org/apache/druid/indexing/common/TestFirehose.java

@@ -47,7 +47,9 @@ public class TestFirehose implements Firehose
     private boolean waitForClose = true;
     private List<Object> seedRows;
 
-    public TestFirehoseFactory() {}
+    public TestFirehoseFactory()
+    {
+    }
 
     public TestFirehoseFactory(boolean waitForClose, List<Object> seedRows)
     {

indexing-service/src/test/java/org/apache/druid/indexing/overlord/http/OverlordTest.java

@@ -408,7 +408,9 @@ public class OverlordTest
     }
 
     @Override
-    public void shutdown(String taskid, String reason) {}
+    public void shutdown(String taskid, String reason)
+    {
+    }
 
     @Override
     public synchronized Collection<? extends TaskRunnerWorkItem> getRunningTasks()

integration-tests/src/test/java/org/apache/druid/tests/indexer/ITAppenderatorDriverRealtimeIndexTaskTest.java

@@ -112,7 +112,9 @@ public class ITAppenderatorDriverRealtimeIndexTaskTest extends AbstractITRealtim
         try {
           Thread.sleep(DELAY_BETWEEN_EVENTS_SECS * 1000);
         }
-        catch (InterruptedException ex) { /* nothing */ }
+        catch (InterruptedException ex) {
+          /* nothing */
+        }
         dtLast = dt; // latest timestamp
         dt = DateTimes.nowUtc();
         i++;

integration-tests/src/test/java/org/apache/druid/tests/indexer/ITRealtimeIndexTaskTest.java

@@ -123,7 +123,9 @@ public class ITRealtimeIndexTaskTest extends AbstractITRealtimeIndexTaskTest
         try {
           Thread.sleep(DELAY_BETWEEN_EVENTS_SECS * 1000);
         }
-        catch (InterruptedException ex) { /* nothing */ }
+        catch (InterruptedException ex) {
+          /* nothing */
+        }
         dtLast = dt;
         dt = DateTimes.nowUtc();
         i++;

pom.xml

@@ -994,7 +994,7 @@
                     <dependency>
                         <groupId>com.puppycrawl.tools</groupId>
                         <artifactId>checkstyle</artifactId>
-                        <version>8.14</version>
+                        <version>8.20</version>
                     </dependency>
                 </dependencies>
                 <executions>

processing/src/main/java/org/apache/druid/query/topn/TopNUtils.java

@@ -45,5 +45,7 @@ final class TopNUtils
     return cursor.getOffset().clone();
   }
 
-  private TopNUtils() {}
+  private TopNUtils()
+  {
+  }
 }

processing/src/main/java/org/apache/druid/segment/Capabilities.java

@@ -51,7 +51,9 @@ public class Capabilities
   {
     private boolean dimensionValuesSorted = false;
 
-    private CapabilitiesBuilder() {}
+    private CapabilitiesBuilder()
+    {
+    }
 
     public CapabilitiesBuilder dimensionValuesSorted(boolean value)
     {

processing/src/main/java/org/apache/druid/segment/DimensionHandlerUtils.java

@@ -51,7 +51,9 @@ public final class DimensionHandlerUtils
   public static final Float ZERO_FLOAT = 0.0f;
   public static final Long ZERO_LONG = 0L;
 
-  private DimensionHandlerUtils() {}
+  private DimensionHandlerUtils()
+  {
+  }
 
   public static final ColumnCapabilities DEFAULT_STRING_CAPABILITIES =
       new ColumnCapabilitiesImpl().setType(ValueType.STRING)

processing/src/main/java/org/apache/druid/segment/IntIteratorUtils.java

@@ -205,5 +205,7 @@ public final class IntIteratorUtils
     return IntLists.unmodifiable(integers);
   }
 
-  private IntIteratorUtils() {}
+  private IntIteratorUtils()
+  {
+  }
 }

processing/src/main/java/org/apache/druid/segment/IntListUtils.java

@@ -25,7 +25,9 @@ import it.unimi.dsi.fastutil.ints.IntList;
 
 public class IntListUtils
 {
-  private IntListUtils() {}
+  private IntListUtils()
+  {
+  }
 
   public static IntList fromTo(int from, int to)
   {

processing/src/main/java/org/apache/druid/segment/NilColumnValueSelector.java

@@ -40,7 +40,9 @@ public class NilColumnValueSelector implements ColumnValueSelector
     return INSTANCE;
   }
 
-  private NilColumnValueSelector() {}
+  private NilColumnValueSelector()
+  {
+  }
 
   /**
    * always returns 0, if {@link NullHandling#NULL_HANDLING_CONFIG_STRING} is set to true,

processing/src/main/java/org/apache/druid/segment/data/BitmapSerde.java

@@ -27,12 +27,16 @@ public class BitmapSerde
   // default bitmap indices for Druid >= 0.7.x
   // annotation required so Jackson doesn't get confused
   @JsonTypeName("concise")
-  public static class DefaultBitmapSerdeFactory extends ConciseBitmapSerdeFactory {}
+  public static class DefaultBitmapSerdeFactory extends ConciseBitmapSerdeFactory
+  {
+  }
 
   // default bitmap indices in Druid <= 0.6.x
   @JsonTypeName("concise")
   // annotation required so Jackson doesn't get confused by subclassing
-  public static class LegacyBitmapSerdeFactory extends ConciseBitmapSerdeFactory {}
+  public static class LegacyBitmapSerdeFactory extends ConciseBitmapSerdeFactory
+  {
+  }
 
   public static BitmapSerdeFactory createLegacyFactory()
   {

processing/src/main/java/org/apache/druid/segment/serde/MetaSerdeHelper.java

@@ -38,7 +38,9 @@ public final class MetaSerdeHelper<T>
 
   private final List<FieldWriter<T>> fieldWriters = new ArrayList<>();
 
-  private MetaSerdeHelper() {}
+  private MetaSerdeHelper()
+  {
+  }
 
   public MetaSerdeHelper<T> writeInt(IntFieldWriter<T> fieldWriter)
   {

processing/src/main/java/org/apache/druid/segment/writeout/OffHeapMemorySegmentWriteOutMediumFactory.java

@@ -34,7 +34,9 @@ public class OffHeapMemorySegmentWriteOutMediumFactory implements SegmentWriteOu
     return INSTANCE;
   }
 
-  private OffHeapMemorySegmentWriteOutMediumFactory() {}
+  private OffHeapMemorySegmentWriteOutMediumFactory()
+  {
+  }
 
   @Override
   public SegmentWriteOutMedium makeSegmentWriteOutMedium(File outDir)

processing/src/main/java/org/apache/druid/segment/writeout/TmpFileSegmentWriteOutMediumFactory.java

@@ -34,7 +34,9 @@ public final class TmpFileSegmentWriteOutMediumFactory implements SegmentWriteOu
     return INSTANCE;
   }
 
-  private TmpFileSegmentWriteOutMediumFactory() {}
+  private TmpFileSegmentWriteOutMediumFactory()
+  {
+  }
 
   @Override
   public SegmentWriteOutMedium makeSegmentWriteOutMedium(File outDir) throws IOException

processing/src/test/java/org/apache/druid/query/groupby/epinephelinae/ConcurrentGrouperTest.java

@@ -258,7 +258,9 @@ public class ConcurrentGrouperTest
         }
 
         @Override
-        public void reset() {}
+        public void reset()
+        {
+        }
       };
     }
 

processing/src/test/java/org/apache/druid/segment/RowIteratorHelper.java

@@ -39,5 +39,7 @@ public final class RowIteratorHelper
     }
   }
 
-  private RowIteratorHelper() {}
+  private RowIteratorHelper()
+  {
+  }
 }

server/src/main/java/org/apache/druid/indexing/overlord/supervisor/NoopSupervisorSpec.java

@@ -98,10 +98,14 @@ public class NoopSupervisorSpec implements SupervisorSpec
     return new Supervisor()
     {
       @Override
-      public void start() {}
+      public void start()
+      {
+      }
 
       @Override
-      public void stop(boolean stopGracefully) {}
+      public void stop(boolean stopGracefully)
+      {
+      }
 
       @Override
       public SupervisorReport getStatus()
@@ -110,7 +114,9 @@ public class NoopSupervisorSpec implements SupervisorSpec
       }
 
       @Override
-      public void reset(DataSourceMetadata dataSourceMetadata) {}
+      public void reset(DataSourceMetadata dataSourceMetadata)
+      {
+      }
 
       @Override
       public void checkpoint(

server/src/main/java/org/apache/druid/segment/realtime/plumber/NoopSegmentHandoffNotifierFactory.java

@@ -39,10 +39,14 @@ public class NoopSegmentHandoffNotifierFactory implements SegmentHandoffNotifier
     }
 
     @Override
-    public void start() {}
+    public void start()
+    {
+    }
 
     @Override
-    public void close() {}
+    public void close()
+    {
+    }
   };
 
   @Override

server/src/main/java/org/apache/druid/server/coordinator/CuratorLoadQueuePeon.java

@@ -317,7 +317,8 @@ public class CuratorLoadQueuePeon extends LoadQueuePeon
 
   @Override
   public void start()
-  { }
+  {
+  }
 
   @Override
   public void stop()

server/src/main/java/org/apache/druid/server/coordinator/helper/SegmentCompactorUtil.java

@@ -53,5 +53,7 @@ class SegmentCompactorUtil
     return new Interval(largeInterval.getStart(), smallInterval.getStart());
   }
 
-  private SegmentCompactorUtil() {}
+  private SegmentCompactorUtil()
+  {
+  }
 }

server/src/main/java/org/apache/druid/server/coordinator/rules/Rules.java

@@ -40,5 +40,7 @@ public class Rules
     }
   }
 
-  private Rules() {}
+  private Rules()
+  {
+  }
 }

server/src/main/java/org/apache/druid/server/http/RedirectFilter.java

@@ -50,7 +50,9 @@ public class RedirectFilter implements Filter
   }
 
   @Override
-  public void init(FilterConfig filterConfig) {}
+  public void init(FilterConfig filterConfig)
+  {
+  }
 
   @Override
   public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
@@ -85,5 +87,7 @@ public class RedirectFilter implements Filter
   }
 
   @Override
-  public void destroy() {}
+  public void destroy()
+  {
+  }
 }

server/src/main/java/org/apache/druid/server/log/DefaultRequestLogEventBuilderFactory.java

@@ -37,7 +37,9 @@ public final class DefaultRequestLogEventBuilderFactory implements RequestLogEve
     return INSTANCE;
   }
 
-  private DefaultRequestLogEventBuilderFactory() {}
+  private DefaultRequestLogEventBuilderFactory()
+  {
+  }
 
   @Override
   public ServiceEventBuilder<RequestLogEvent> createRequestLogEventBuilder(String feed, RequestLogLine requestLogLine)

server/src/main/java/org/apache/druid/server/log/RequestLogger.java

@@ -31,7 +31,11 @@ public interface RequestLogger
 
   void logSqlQuery(RequestLogLine requestLogLine) throws IOException;
 
-  default void start() throws Exception {}
+  default void start() throws Exception
+  {
+  }
 
-  default void stop() {}
+  default void stop()
+  {
+  }
 }

server/src/test/java/org/apache/druid/client/CachingClusteredClientTestUtils.java

@@ -115,5 +115,7 @@ public final class CachingClusteredClientTestUtils
     return objectMapper;
   }
 
-  private CachingClusteredClientTestUtils() {}
+  private CachingClusteredClientTestUtils()
+  {
+  }
 }

server/src/test/java/org/apache/druid/segment/realtime/firehose/ServiceAnnouncingChatHandlerProviderTest.java

@@ -35,7 +35,9 @@ import org.junit.runner.RunWith;
 @RunWith(EasyMockRunner.class)
 public class ServiceAnnouncingChatHandlerProviderTest extends EasyMockSupport
 {
-  private static class TestChatHandler implements ChatHandler {}
+  private static class TestChatHandler implements ChatHandler
+  {
+  }
 
   private static final String TEST_SERVICE_NAME = "test-service-name";
   private static final String TEST_HOST = "test-host";

server/src/test/java/org/apache/druid/server/AsyncManagementForwardingServletTest.java

@@ -472,9 +472,13 @@ public class AsyncManagementForwardingServletTest extends BaseJettyTest
     }
 
     @Override
-    public void registerListener(Listener listener) {}
+    public void registerListener(Listener listener)
+    {
+    }
 
     @Override
-    public void unregisterListener() {}
+    public void unregisterListener()
+    {
+    }
   }
 }

server/src/test/java/org/apache/druid/server/metrics/NoopServiceEmitter.java

@@ -30,5 +30,7 @@ public class NoopServiceEmitter extends ServiceEmitter
   }
 
   @Override
-  public void emit(Event event) {}
+  public void emit(Event event)
+  {
+  }
 }

services/src/main/java/org/apache/druid/cli/ServerRunnable.java

@@ -96,7 +96,9 @@ public abstract class ServerRunnable extends GuiceRunnable
    */
   protected static class DiscoverySideEffectsProvider implements Provider<DiscoverySideEffectsProvider.Child>
   {
-    public static class Child {}
+    public static class Child
+    {
+    }
 
     public static class Builder
     {